Abstract
Objective:
Ovarian cancer (OC) is the deadliest gynecological malignancy, with patients experiencing late diagnosis and high recurrence. AXL is highly expressed in OC and correlates with worse prognosis. We aim to evaluate the use of AXL-targeting nanobodies as a novel therapeutic modality to inhibit the AXL-GAS6 axis in OC.
Methods:
ID8-fLuc cells were in vivo passaged three times to obtain the fast-progressing P3 ID8 Thy1.1 cell line. The expression of AXL in ID8 lines was assessed by flow cytometry and immunofluorescence, while serum GAS6 levels in tumor-bearing and naïve mice were measured by ELISA. Using in silico analyses, we correlated AXL and GAS6 expression with OC patient outcomes and assessed AXL expression in different tissues and patient cohorts. Orthotopic ovarian tumors were processed to a single cell suspension and treated in vitro with the nanobody (AXL-Fc), a PARP inhibitor (Olaparib), or controls (PBS or DMSO) for 24 h or 72 h, followed by flow cytometry to assess stages of cell death and cancer cell proliferation.
Results:
In vivo passaging of ID8-fLuc cells resulted in a faster-progressing P3 ID8 Thy1.1 cell line that recapitulates stages I-III observed in OC patients. In OC patients, AXL and GAS6 genes are highly expressed in primary and metastatic tumors, and enriched in platinum-resistant patients. AXL-Fc induces necrosis in OC cells from orthotopic ovarian tumors. AXL-Fc synergizes with Olaparib, resulting in decreased OC cell proliferation.
Conclusions:
Leveraging the synergistic effects of AXL-Fc with Olaparib, we propose a new AXL-targeting treatment approach for OC that warrants further investigation.